<?php
class A {
	function show() {
		echo 'A';
	}
}

class B extends A {
	function show() {
		echo 'B';
	}

	private function hello() {
		echo 'Error';
	}
}

class C extends B {

	function show() {
		echo 'C';
	}

	function showA() {
		A::show();
	}

	function showB() {
		B::show();
	}

	function showClosure() {
		$count = 0;
		return function() use (&$count) {echo $count++;};
	}
}
$c = new C();
$c->showA();
$c->showB();
$c->show();
$c->showClosure();
$c->showClosure();
$c->showClosure();

// 报错
$c->hello();